Chassis
We would argue the X3 is more deserving of M status than the X5 or X6. Why is that? Well, the curb weight for one. The F25 X3 in N55 X35i trim weighs only 3971 pounds. This is a whopping 1,397 pounds less than the X5 M and 1,353 pounds less than the X6 M. An M model of the X3 would weigh a bit more than standard (larger tires/wheels, brakes) so let's just say an X3 M would be at least 1,200 pounds lighter than the X5 or X6 M cars if it were to use a 6 cylinder turbo.
1,200 pounds is no joke, that is a serious difference in heft. Not only would an X3 M stop and handle better, it would get better mileage and require far less power to achieve the same performance numbers as its big brothers. Here is a power to weight example, the X5 M needs 555 horsepower to achieve 9.67 pounds per hp. For an X3 M to achieve this same power to weight ratio, it would need only 429 horsepower at a curb weight of 4,150 pounds.
Drivetrain and Motor
What motor would an F25 X3 M have? Well, the N55 turbo 6 makes the most sense. Why? Because this motor is already used in the X3 first of all. Secondly, BMW is going to use an N55 variant for the next generation M3. In much the same way the X5 and X6 M serve as a preview to the next generation F10 M5's motor using the same base motor, the X3 M would no doubt do the same for the next generation M3. Quite logical, isn't it?
The transmission would be an automatic. Why? Well, a dual clutch setup in an SUV does not make too much sense as it still needs to function as an SUV. An auto makes much more sense for those that want to tow and actually get some utility out of the vehicle. A manual should not be ruled out but probably has a slim chance as well. If it happens, count on a 6 speed automatic that is shared with the X5 and X6 M. Keep in mind, Porsche also ditches the PDK for the Cayenne for utility reasons. AWD will obviously be standard.
What will the performance numbers be?
The current N55 based X3 is BMW estimated to do 0-60 in 5.5 seconds. It should do the 1/4 mile in the low 14's and be quite close to an E36 M3 in acceleration. We do not see an M version having a superior power to weight ratio to the X5 or X6 M. 400-430hp is a reasonable guess on paper and should propel X3 M into the high 12's in the 1/4 at just under 110 mph. 0-60 would be in the mid 4's. The X5 and X6 M would still have a top end advantage due to the raw horsepower difference and the hierarchy would be maintained. The difference would be similar to that of the E92 M3 vs. E60 M5, 2 to 3 mph in trap speed stock for stock.
The handling and braking will no doubt be in the X3 M's favor. Car and Driver pulled .89 g in the X5 M. The X3 M would be able to improve on this a bit. The thought of an SUV pulling over .90 easily is just incredible in of itself. With so much less heft braking would improve on the X5 M's 162 feet from 70 mph.
Does it makes sense?
We think it makes more sense than an X5 or X6 M. If M SUV's are here, BMW might as well do them right. With an X3 M, BMW has the potential to have the most exciting performance SUV in the marketplace. It would be the lightest, the best handling, most efficient, simply the best performance SUV driving experience available. If they had the balls to put the V8 twin turbo in it they would stomp everything out there for years to come.
Think of it this way, does it make sense for BMW to have an M3? Of course, no one could imagine the M lineup without it due to the driving experience. The E92 M3 weighs only about 400 pounds less than the E60 M5. Imagine if this difference was over 1200 pounds.
Hell, an M version of the 1 series is on its way and it potentially will be the lightest and most fun M car for sale today. The M brand has already been diluted, might as well dilute it the right way with cars that are lighter and more fun to drive. We say bring on the X3 M, and after that, might as well do an X4 M too.
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